scholarly journals Constitutive Activation of β-Catenin in Differentiated Osteoclasts Induces Bone Loss in Mice

2018 ◽  
Vol 48 (5) ◽  
pp. 2091-2102 ◽  
Author(s):  
Xin Sui ◽  
Shijian Deng ◽  
Mengmeng Liu ◽  
Linlin Fan ◽  
Yunfei Wang ◽  
...  

Background/Aims: Activation of the Wnt/β-catenin signalling pathway has been widely investigated in bone biology and shown to promote bone formation. However, its specific effects on osteoclast differentiation have not been fully elucidated. Our study aimed to identify the role of β-catenin in osteoclastogenesis and bone homeostasis. Methods: In the present study, exon 3 in the β-catenin gene (Ctnnb1) allele encoding phosphorylation target serine/threonine residues was flanked by floxP sequences. We generated mice exhibiting conditional β-catenin activation (Ctsk-Cre;Ctnnb1flox(exon3)/+, designated CA-β-catenin) by crossing Ctnnb1flox(exon3)/flox(exon3) mice with osteoclast-specific Ctsk-Cre mice. Bone growth and bone mass were analysed by micro-computed tomography (micro-CT) and histomorphometry. To further examine osteoclast activity, osteoclasts were induced from bone marrow monocytes (BMMs) isolated from CA-β-catenin and Control mice in vitro. Osteoclast differentiation was detected by tartrate-resistant acid phosphatase (TRAP) staining, immunofluorescence staining and reverse transcription-quantitative PCR (RT–qPCR) analysis. Results: Growth retardation and low bone mass were observed in CA-β-catenin mice. Compared to controls, CA-β-catenin mice had significantly reduced trabecular bone numbers under growth plates as well as thinner cortical bones. Moreover, increased TRAP-positive osteoclasts were observed on the surfaces of trabecular bones and cortical bones in the CA-β-catenin mice; consistent results were observed in vitro. In the CA-β-catenin group, excessive numbers of osteoclasts were induced from BMMs, accompanied by the increased expression of osteoclast-associated marker genes. Conclusion: These results indicated that the constitutive activation of β-catenin in osteoclasts promotes osteoclast formation, resulting in bone loss.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Peerapat Visitchanakun ◽  
Worasit Saiworn ◽  
Prapaporn Jongwattanapisan ◽  
Asada Leelahavanichkul ◽  
Prapaporn Pisitkun ◽  
...  

AbstractOsteoporotic fracture is a major cause of morbidity in patients with systemic lupus erythematosus (SLE). Mice lacking Fc gamma receptor IIb (FcγRIIB) spontaneously develop lupus-like disease or SLE at 6-month-old. The aim of this study was to investigate whether FcγRIIB deletion induces osteopenia. μCT analysis indicated that deleting FcγRIIB did not affect cancellous bone microarchitecture in 3-month-old mice in which SLE had not yet developed. However, 6- and 10-month-old FcγRIIB−/− males that developed an SLE-like phenotype were osteopenic and FcγRIIB deletion resulted in decreased cancellous bone volume. Histomorphometry confirmed a significant decrease in cancellous bone volume in 6- and 10-month-old FcγRIIB−/− males. The osteoclast number was increased without any change in osteoblast number. In vitro assays indicated that deleting FcγRIIB increased osteoclast differentiation while alkaline phosphatase activity and mineralization were unaltered. These changes were associated with increases in steady-state mRNA levels for the osteoclast marker genes Trap and Ctsk. Moreover, FcγRIIB−/− mice had higher level of serum TNFα, a proinflammatory cytokine. A soluble TNFα receptor, etanercept, prevented cancellous bone loss in FcγRIIB−/− mice. Our results indicate that FcγRIIB indirectly regulates cancellous bone homeostasis following SLE development. FcγRIIB deletion induces inflammatory bone loss due to increased TNFα-mediated bone resorption without any change in bone formation in mice with SLE-like syndrome.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wida Razawy ◽  
Celso H. Alves ◽  
Marijke Koedam ◽  
Patrick S. Asmawidjaja ◽  
Adriana M. C. Mus ◽  
...  

AbstractThe IL-23 receptor (IL-23R) signaling pathway has pleiotropic effects on the differentiation of osteoclasts and osteoblasts, since it can inhibit or stimulate these processes via different pathways. However, the potential role of this pathway in the regulation of bone homeostasis remains elusive. Therefore, we studied the role of IL-23R signaling in physiological bone remodeling using IL-23R deficient mice. Using µCT, we demonstrate that 7-week-old IL-23R−/− mice have similar bone mass as age matched littermate control mice. In contrast, 12-week-old IL-23R−/− mice have significantly lower trabecular and cortical bone mass, shorter femurs and more fragile bones. At the age of 26 weeks, there were no differences in trabecular bone mass and femur length, but most of cortical bone mass parameters remain significantly lower in IL-23R−/− mice. In vitro osteoclast differentiation and resorption capacity of 7- and 12-week-old IL-23R−/− mice are similar to WT. However, serum levels of the bone formation marker, PINP, are significantly lower in 12-week-old IL-23R−/− mice, but similar to WT at 7 and 26 weeks. Interestingly, Il23r gene expression was not detected in in vitro cultured osteoblasts, suggesting an indirect effect of IL-23R. In conclusion, IL-23R deficiency results in temporal and long-term changes in bone growth via regulation of bone formation.


Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 199
Author(s):  
Urara Tanaka ◽  
Shunichi Kajioka ◽  
Livia S. Finoti ◽  
Daniela B. Palioto ◽  
Denis F. Kinane ◽  
...  

DNA methylation controls several inflammatory genes affecting bone homeostasis. Hitherto, inhibition of DNA methylation in vivo in the context of periodontitis and osteoclastogenesis has not been attempted. Ligature-induced periodontitis in C57BL/6J mice was induced by placing ligature for five days with Decitabine (5-aza-2′-deoxycytidine) (1 mg/kg/day) or vehicle treatment. We evaluated bone resorption, osteoclast differentiation by tartrate-resistant acid phosphatase (TRAP) and mRNA expression of anti-inflammatory molecules using cluster differentiation 14 positive (CD14+) monocytes from human peripheral blood. Our data showed that decitabine inhibited bone loss and osteoclast differentiation experimental periodontitis, and suppressed osteoclast CD14+ human monocytes; and conversely, that it increased bone mineralization in osteoblastic cell line MC3T3-E1 in a concentration-dependent manner. In addition to increasing IL10 (interleukin-10), TGFB (transforming growth factor beta-1) in CD14+ monocytes, decitabine upregulated KLF2 (Krüppel-like factor-2) expression. Overexpression of KLF2 protein enhanced the transcription of IL10 and TGFB. On the contrary, site-directed mutagenesis of KLF2 binding site in IL10 and TFGB abrogated luciferase activity in HEK293T cells. Decitabine reduces bone loss in a mouse model of periodontitis by inhibiting osteoclastogenesis through the upregulation of anti-inflammatory cytokines via KLF2 dependent mechanisms. DNA methyltransferase inhibitors merit further investigation as a possible novel therapy for periodontitis.


2012 ◽  
Vol 199 (7) ◽  
pp. 1145-1158 ◽  
Author(s):  
Hyung Joon Kim ◽  
Vikram Prasad ◽  
Seok-Won Hyung ◽  
Zang Hee Lee ◽  
Sang-Won Lee ◽  
...  

The precise regulation of Ca2+ dynamics is crucial for proper differentiation and function of osteoclasts. Here we show the involvement of plasma membrane Ca2+ ATPase (PMCA) isoforms 1 and 4 in osteoclastogenesis. In immature/undifferentiated cells, PMCAs inhibited receptor activator of NF-κB ligand–induced Ca2+ oscillations and osteoclast differentiation in vitro. Interestingly, nuclear factor of activated T cell c1 (NFATc1) directly stimulated PMCA transcription, whereas the PMCA-mediated Ca2+ efflux prevented NFATc1 activation, forming a negative regulatory loop. PMCA4 also had an anti-osteoclastogenic effect by reducing NO, which facilitates preosteoclast fusion. In addition to their role in immature cells, increased expression of PMCAs in mature osteoclasts prevented osteoclast apoptosis both in vitro and in vivo. Mice heterozygous for PMCA1 or null for PMCA4 showed an osteopenic phenotype with more osteoclasts on bone surface. Furthermore, PMCA4 expression levels correlated with peak bone mass in premenopausal women. Thus, our results suggest that PMCAs play important roles for the regulation of bone homeostasis in both mice and humans by modulating Ca2+ signaling in osteoclasts.


2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Jiachao Guo ◽  
Ranyue Ren ◽  
Kai Sun ◽  
Xudong Yao ◽  
Jiamin Lin ◽  
...  

Abstract Osteoclasts are multinucleated giant cells with the ability to degrade bone tissue, and are closely related to abnormal bone metabolic diseases. Endoplasmic reticulum (ER) is an organelle responsible for protein modification, quality control, and transportation. The accumulation of unfolded or misfolded proteins in ER cavity induces ER stress. Double-stranded RNA-dependent protein kinase-like ER kinase (PERK) is an ER stress-sensing protein, which is ubiquitous in eukaryotic cells. Systemic PERK knockout mice show severe bone loss, suggesting that PERK is of great significance for maintaining the normal growth and development of bone tissue, but the role of PERK in osteoclastogenesis is still unclear. In this study, we found that PERK was significantly activated during RANKL-induced osteoclast differentiation; knockdown of PERK by siRNA and inhibition of PERK by GSK2606414, respectively, had significant negative regulatory effects on the formation and bone resorption of osteoclasts. PERK inhibitor GSK2606414 down-regulated the mRNA levels and protein expression of osteoclast differentiation marker genes, and inhibited RANKL-induced activation of Mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways. Treatment with PERK inhibitor GSK2606414 in ovariectomized mouse model significantly suppressed bone loss and osteoclast formation. Thapsigargin activated ER stress to enhance autophagy, while GSK2606414 had a significant inhibitory effect on autophagy flux and autophagosome formation. Antioxidant N-acetylcysteine (NAC) could inhibit the expression of PERK phosphorylation, osteoclast-related proteins and autophagy-related proteins, but the use of PERK activator CCT020312 can reverse inhibition effect of NAC. Our findings demonstrate a key role for PERK in osteoclast differentiation and suggest its therapeutic potential.


Nutrients ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 3904
Author(s):  
So Young Eun ◽  
Yoon-Hee Cheon ◽  
Gyeong Do Park ◽  
Chong Hyuk Chung ◽  
Chang Hoon Lee ◽  
...  

Vigeo is a mixture of fermented extracts of Eleutherococcus senticosus Maxim (ESM), Achyranthes japonica (Miq.) Nakai (AJN), and Atractylodes japonica Koidzumi (AJK) manufactured using the traditional Korean nuruk fermentation method. Although the bioactive effects of ESM, AJN, and AJK have already been reported, the pharmacological effects of Vigeo have not been proven. Therefore, in this study, we investigated whether Vigeo had inhivitory effects on lipopolysaccharide (LPS)-induced inflammatory bone loss in vivo and receptor activator of nuclear factor-B ligand (RANKL)-induced osteoclastogenesis and the related mechanism in vitro. Vigeo administration conferred effective protection against bone loss induced by excessive inflammatory response and activity of osteoclasts in LPS-induced inflammatory osteoporosis mouse model. In addition, Vigeo significantly suppressed the formation of tartrate-resistant acid phosphatase-positive osteoclasts induced by RANKL and inhibited F-actin formation and bone resorbing activity without any cytotoxicity. Moreover, Vigeo significantly inhibited RANKL-induced phosphorylation of p38, ERK, JNK, IκB, and AKT and degradation of IkB. Additionally, Vigeo strongly inhibited the mRNA and protein expression of c-FOS and NFATc1 and subsequently attenuated the expression of osteoclast specific marker genes induced by RANKL. We demonstrated for the first time the anti-osteoporosis effect of Vigeo, suggesting that it could be a potential therapeutic candidate for the treatment of osteoclast-mediated inflammatory bone diseases.


2022 ◽  
Vol 12 ◽  
Author(s):  
Sungyub Lee ◽  
Minsun Kim ◽  
Sooyeon Hong ◽  
Eom Ji Kim ◽  
Jae-Hyun Kim ◽  
...  

Postmenopausal osteoporosis is caused by an imbalance between osteoclasts and osteoblasts and causes severe bone loss. Osteoporotic medicines are classified into bone resorption inhibitors and bone formation promoters according to the mechanism of action. Long-term use of bisphosphonate and selective estrogen receptor modulators (SERMs) can cause severe side effects in postmenopausal osteoporosis patients. Therefore, it is important to find alternative natural products that reduce osteoclast activity and increase osteoblast formation. Sparganii Rhizoma (SR) is the dried tuberous rhizome of Sparganium stoloniferum Buchanan-Hamilton and is called “samreung” in Korea. However, to date, the effect of SR on osteoclast differentiation and the ovariectomized (OVX)-induced bone loss model has not been reported. In vitro, tartrate-resistant acid phosphatase (TRAP) staining, western blots, RT-PCR and other methods were used to examine the effect of SR on osteoclast differentiation and osteoblasts. In vivo, we confirmed the effect of SR in a model of OVX-induced postmenopausal osteoporosis. SR inhibited osteoclast differentiation and decreased the expression of TNF receptor-associated factor 6 (TRAF6), nuclear factor of activated T cells 1 (NFATc1) and c-Fos pathway. In addition, SR stimulates osteoblast differentiation and increased protein expression of the bone morphogenetic protein 2 (BMP-2)/SMAD signaling pathway. Moreover, SR protected against bone loss in OVX-induced rats. Our results appear to advance our knowledge of SR and successfully demonstrate its potential role as a osteoclastogenesis-inhibiting and osteogenesis-promoting herbal medicine for the treatment of postmenopausal osteoporosis.


2016 ◽  
Vol 36 (19) ◽  
pp. 2451-2463 ◽  
Author(s):  
Takashi Iezaki ◽  
Kazuya Fukasawa ◽  
Gyujin Park ◽  
Tetsuhiro Horie ◽  
Takashi Kanayama ◽  
...  

Bone homeostasis is maintained by the synergistic actions of bone-resorbing osteoclasts and bone-forming osteoblasts. Here, we show that the transcriptional coactivator/repressor interferon-related developmental regulator 1 (Ifrd1) is expressed in osteoclast lineages and represents a component of the machinery that regulates bone homeostasis. Ifrd1 expression was transcriptionally regulated in preosteoclasts by receptor activator of nuclear factor κB (NF-κB) ligand (RANKL) through activator protein 1. Global deletion of murineIfrd1increased bone formation and decreased bone resorption, leading to a higher bone mass. Deletion ofIfrd1in osteoclast precursors prevented RANKL-induced bone loss, although no bone loss was observed under normal physiological conditions. RANKL-dependent osteoclastogenesis was impairedin vitroinIfrd1-deleted bone marrow macrophages (BMMs).Ifrd1deficiency increased the acetylation of p65 at residues K122 and K123 via the inhibition of histone deacetylase-dependent deacetylation in BMMs. This repressed the NF-κB-dependent transcription of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), an essential regulator of osteoclastogenesis. These findings suggest that an Ifrd1/NF-κB/NFATc1 axis plays a pivotal role in bone remodelingin vivoand represents a therapeutic target for bone diseases.


Author(s):  
Hsiang Chou ◽  
Michael P Grant ◽  
Alicia M Bolt ◽  
Cynthia Guilbert ◽  
Dany Plourde ◽  
...  

Abstract Tungsten is a naturally occurring metal that is increasingly used in industry and medical devices, and is labeled as an emerging environmental contaminant. Like many metals, tungsten accumulates in bone. Our previous data indicate that tungsten decreases differentiation of osteoblasts, bone-forming cells. Herein, we explored the impact of tungsten on osteoclast differentiation, which function in bone resorption. We observed significantly elevated osteoclast numbers in the trabecular bone of femurs following oral exposure to tungsten in male, but not female mice. In order to explore the mechanism(s) by which tungsten increases osteoclast number, we utilized in vitro murine primary and cell line pre-osteoclast models. Although tungsten did not alter the adhesion of osteoclasts to the extracellular matrix protein, vitronectin, we did observe that tungsten enhanced RANKL-induced differentiation into tartrate-resistant acid phosphatase (TRAP)-positive mononucleated osteoclasts. Importantly, tungsten alone had no effect on differentiation or on the number of multinucleated TRAP-positive osteoclasts. Enhanced RANKL-induced differentiation correlated with increased gene expression of differentiated osteoclast markers Nfatc1, Acp5, and Ctsk. Although tungsten did not alter the RANK surface receptor expression, it did modulate its downstream signaling. Co-exposure of tungsten and RANKL resulted in sustained positive p38 signaling. These findings demonstrate that tungsten enhances sex-specific osteoclast differentiation, and together with previous findings of decreased osteoblastogenesis, implicate tungsten as a modulator of bone homeostasis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Kyosuke Sakaida ◽  
Kazuhiro Omori ◽  
Masaaki Nakayama ◽  
Hiroki Mandai ◽  
Saki Nakagawa ◽  
...  

Osteoporosis is a common disease characterized by a systemic impairment of bone mass and microarchitecture that results in fragility fractures. Severe bone loss due to osteoporosis triggers pathological fractures and consequently decreases the daily life activity and quality of life. Therefore, prevention of osteoporosis has become an important issue to be addressed. We have reported that the fungal secondary metabolite (+)-terrein (TER), a natural compound derived from Aspergillus terreus, has shown receptor activator of nuclear factor-κB ligand (RANKL)–induced osteoclast differentiation by suppressing nuclear factor of activated T-cell 1 (NFATc1) expression, a master regulator of osteoclastogenesis. TER has been shown to possess extensive biological and pharmacological benefits; however, its effects on bone metabolism remain unclear. In this study, we investigated the effects of TER on the femoral bone metabolism using a mouse-ovariectomized osteoporosis model (OVX mice) and then on RANKL signal transduction using mouse bone marrow macrophages (mBMMs). In vivo administration of TER significantly improved bone density, bone mass, and trabecular number in OVX mice (p < 0.01). In addition, TER suppressed TRAP and cathepsin-K expression in the tissue sections of OVX mice (p < 0.01). In an in vitro study, TER suppressed RANKL-induced phosphorylation of PKCα/βII, which is involved in the expression of NFATc1 (p < 0.05). The PKC inhibitor, GF109203X, also inhibited RANKL-induced osteoclastogenesis in mBMMs as well as TER. In addition, TER suppressed the expression of osteoclastogenesis-related genes, such as Ocstamp, Dcstamp, Calcr, Atp6v0d2, Oscar, and Itgb3 (p < 0.01). These results provide promising evidence for the potential therapeutic application of TER as a novel treatment compound against osteoporosis.


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